The present invention relates to a device for cooling the compressor of a thermal compression machine and more particularly to a means for priming this device of the thermo-siphon type.
A conventional thermal compression machine comprises in series a compressor, a condenser, an expansion valve and an evaporator, connected together by tubes to form a closed circuit through which flows a fluid.
The fluid undergoes all along this closed circuit pressure and temperature variations. Compressed by the compressor, it is liquified inside the condenser then, after passing through the expansion valve, it is evaporated in the evaporator.
Depending on the conditions of use, a thermal compression machine may operate as a refrigerator or as a heat pump.
When the thermal machine operates as a refrigerator, the fluid is evaporated in the evaporator while yielding up cold to the environment which surrounds it and is liquified in the condenser while taking cold from the environment which surrounds it.
When the thermal machine operates as a heat pump, the fluid is evaporated in the evaporator while taking heat from the environment which surrounds it and is liquified in the condenser while restoring heat to the environment which surrounds it.
So as to avoid excessive heating of the compressor, such a compressor is equipped with a cooling circuit. This cooling circuit is advantageously formed by a thermo-siphon comprising an evaporator immersed in the oil of the compressor and a condenser, connected together by two tubes so as to form a closed circuit through which a fluid flows.
When the thermo-siphon is primed, the fluid, while evaporating in the evaporator, takes heat from the oil of the compressor, which is the object sought, and restores it to the external environment while liquifying in the condenser.
At the time of starting up the compressor, there occurs a transitory period during which the evaporation of the fluid contained in the thermo-siphon is not yet at its maximum, the evaporation only reaching its maximum when the compressor reaches its permanent operating conditions, the temperature of the oil then being substantially equal to that of the compressor.
Consequently, at the time of starting up the compressor, the cooling of the compressor is only provided gradually.
Now, so as to maintain the compressor, and consequently the whole of the installation, under good operating conditions, it is desirable, as soon as the compressor is started up, that this latter be cooled under optimum conditions.
Furthermore, the cyclic operation of the compression machine is prejudicial to maintaining the thermo-siphon under optimum operating conditions.